diff --git a/oml/setup.py b/oml/setup.py
index e676292..ee62cb6 100644
--- a/oml/setup.py
+++ b/oml/setup.py
@@ -423,6 +423,27 @@ def upgrade_db(old, new=None):
                         )''')
             run_sql('CREATE UNIQUE INDEX IF NOT EXISTS user_metadata_index ON user_metadata(id, user_id)')
             run_sql('CREATE INDEX ix_user_metadata_data_hash ON user_metadata (data_hash)')
+    if old <= '20240608-1469-647a8b9':
+        old_hostname = os.path.join(settings.data_path, 'tor/hostname')
+        if os.path.exists(old_hostname):
+            with open(old_hostname) as fd:
+                OLD_USER_ID = fd.read().split('.')[0]
+                statements = [
+                    "UPDATE user SET id = '{nid}' WHERE id = '{oid}'",
+                    "UPDATE list SET user_id = '{nid}' WHERE user_id = '{oid}'",
+                    "UPDATE useritem SET user_id = '{nid}' WHERE user_id = '{oid}'",
+                    "UPDATE changelog SET user_id = '{nid}' WHERE user_id = '{oid}'",
+                ]
+                run_sql([
+                    sql.format(oid=OLD_USER_ID, nid=settings.USER_ID)
+                    for sql in statements
+                ])
+                for ext in ('log', 'db', 'json'):
+                    old_log = os.path.join(settings.data_path, 'peers/%s.%s' % (OLD_USER_ID, ext))
+                    new_log = os.path.join(settings.data_path, 'peers/%s.%s' % (USER_ID, ext))
+                    if os.path.exists(old_log) and not os.path.exists(new_log):
+                        os.rename(old_log, new_log)
+
 
 def create_default_lists(user_id=None):
     with db.session():
diff --git a/oml/utils.py b/oml/utils.py
index 80c82dc..51295a4 100644
--- a/oml/utils.py
+++ b/oml/utils.py
@@ -596,3 +596,22 @@ def time_cache(max_age, maxsize=128, typed=False):
         return _wrapped
 
     return _decorator
+
+def migrate_userid(old_id, new_id):
+    from db import run_sql
+    import settings
+    statements = [
+        "UPDATE user SET id = '{nid}' WHERE id = '{oid}'",
+        "UPDATE list SET user_id = '{nid}' WHERE user_id = '{oid}'",
+        "UPDATE useritem SET user_id = '{nid}' WHERE user_id = '{oid}'",
+        "UPDATE changelog SET user_id = '{nid}' WHERE user_id = '{oid}'",
+    ]
+    run_sql([
+        sql.format(oid=old_id, nid=new_id)
+        for sql in statements
+    ])
+    for ext in ('log', 'db', 'json'):
+        old_file = os.path.join(settings.data_path, 'peers/%s.%s' % (old_id, ext))
+        new_file = os.path.join(settings.data_path, 'peers/%s.%s' % (new_id, ext))
+        if os.path.exists(old_file) and not os.path.exists(new_file):
+            os.rename(old_file, new_file)